Luminescence Properties of Sr2MgSi2O7:Eu2+, Ce3+ Phosphor by Solid State Reaction Method

AbstractThe Sr2MgSi2O7:Eu2+, Ce3+ phosphor was prepared by solid state reaction method, boric acid (H3BO3) was added as flux. The phase structure of Sr2MgSi2O7:Eu2+, Ce3+ phosphor was akermanite type structure which belongs to the tetragonal crystallography with space group this structure is a member of the melilite group and forms layered compound. EDX and FTIR spectra confirm the present elements in Sr2MgSi2O7:Eu2+, Ce3+ phosphor. Three peaks in excitation spectra were found at 253, 293, 325nm and corresponding emission peak was recorded at 465nm, belonging to the broad emission ascribed to the 4f65d1→4f7 transition of Eu2+. The ML intensity of prepared phosphor was increasing linearly with increases of mechanical load

Food Restriction-Induced Changes in Gonadotropin-Inhibiting Hormone Cells are Associated with Changes in Sexual Motivation and Food Hoarding, but not Sexual Performance and Food Intake

We hypothesized that putative anorectic and orexigenic peptides control the motivation to engage in either ingestive or sex behaviors, and these peptides function to optimize reproductive success in environments where energy fluctuates. Here, the putative orexigenic peptide, gonadotropin-inhibiting hormone (GnIH, also known as RFamide-related peptide-3), and the putative anorectic hormones leptin, insulin, and estradiol were examined during the course of food restriction. Groups of female Syrian hamsters were restricted to 75% of their ad libitum food intake or fed ad libitum for 4, 8, or 12 days. Two other groups were food-restricted for 12 days and then re-fed ad libitum for 4 or 8 days. After testing for sex and ingestive behavior, blood was sampled and assayed for peripheral hormones. Brains were immunohistochemically double-labeled for GnIH and the protein product of the immediate early gene, c-fos, a marker of cellular activation. Food hoarding, the number of double-labeled cells, and the percent of GnIH-Ir cells labeled with Fos-Ir were significantly increased at 8 and 12 days after the start of food restriction. Vaginal scent marking and GnIH-Ir cell number significantly decreased after the same duration of restriction. Food hoarding, but not food intake, was significantly positively correlated with cellular activation in GnIH-Ir cells. Vaginal scent marking was significantly negatively correlated with cellular activation in GnIH-Ir cells. There were no significant effects of food restriction on plasma insulin, leptin, estradiol, or progesterone concentrations. In the dorsomedial hypothalamus (DMH) of energetically challenged females, strong projections from NPY-Ir cells were found in close apposition to GnIH-Ir cells. Together these results are consistent with the idea that metabolic signals influence sexual and ingestive motivation via NPY fibers that project to GnIH cells in the DMH

Mechanoluminescence properties of SrAl2O4: Tb3+ phosphor

Through the execution of experimental investigation, Mechanoluminescence of SrAl2O4:Tb3+ phosphor was studied which is synthesized by combustion method. In the observation, the peak value of ML depends on the different impact velocity. It was seen that at 55 cm height, the maximum peak of ML is obtained.&nbsp

Europium doped di-calcium magnesium di-silicate orange–red emitting phosphor by solid state reaction method

A new orange–red europium doped di-calcium magnesium di-silicate (Ca2MgSi2O7:Eu3+) phosphor was prepared by the traditional high temperature solid state reaction method. The prepared Ca2MgSi2O7:Eu3+ phosphor was characterized by X-ray diffractometer (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) with energy dispersive x-ray spectroscopy (EDX), fourier transform infrared spectra (FTIR), photoluminescence (PL) and decay characteristics. The phase structure of sintered phosphor was akermanite type structure which belongs to the tetragonal crystallography with space group P4¯21m, this structure is a member of the melilite group and forms a layered compound. The chemical composition of the sintered Ca2MgSi2O7:Eu3+ phosphor was confirmed by EDX spectra. The PL spectra indicate that Ca2MgSi2O7:Eu3+ can be excited effectively by near ultraviolet (NUV) light and exhibit bright orange–red emission with excellent color stability. The fluorescence lifetime of Ca2MgSi2O7:Eu3+ phosphor was found to be 28.47 ms. CIE color coordinates of Ca2MgSi2O7:Eu3+ phosphor is suitable as orange-red light emitting phosphor with a CIE value of (X = 0.5554, Y = 0.4397). Therefore, it is considered to be a new promising orange–red emitting phosphor for white light emitting diode (LED) application

UV and gamma ray induced thermoluminescence properties of cubic Gd2O3:Er3+ phosphor

This paper reports the thermoluminescence properties of Er3+ doped gadolinium oxide nanophosphor. The phosphor is prepared by high temperature solid state reaction method. The method is suitable for large scale production. Starting materials used for sample preparation were Gd2O3, Er2O3 (0.5–2.5 mol%) and fixed concentration of boric acid using as a flux. The prepared samples were characterized by X-ray diffraction technique and the particle size calculated by Scherer's formula. The surface morphology of prepared phosphor is determined by scanning electron microscopic (SEM) technique. Functional group analysis was done by Fourier transform infra-red spectroscopy (FTIR) analysis. The elemental analysis of prepared sample was determined by energy dispersive X-ray analysis (EDX) and the exact particle size of prepared phosphor for the different concentration of dopant (Er3+) was evaluated by transmission electron microscopy (TEM) technique. The prepared phosphors for different concentration of Er3+ were examined by thermoluminescence (TL) glow curve for UV and gamma irradiation. The UV 254 nm source was used for UV irradiation and Co60 source was used for gamma irradiation. The samples show well resolved broad peak covered the temperature range 50–250 °C and the peak temperature found at 126 °C for UV irradiation and higher temperature peak at 214 °C for gamma irradiation. The effect of heating rate on TL studies was presented for optimized sample. Here UV irradiated sample shows the formation of shallow trap (surface trapping) and the gamma irradiated sample shows the formation of deep trapping. The estimation of trap formation was evaluated by knowledge of trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by peak shape method. Here most of the peak shows second order of kinetics. The effect of gamma and UV exposure on TL studies was also examined and it shows linear and sublinear response with dose which indicates that the sample may be useful for TL dosimetry. Keywords: Thermoluminescence, Gamma irradiation, UV irradiated, TL dosimetry, Activation energy, Order of kinetics, Frequency facto

Evaporation losses control in water surface by chemicals

The extremely high rate of Evaporation from water surfaces day by day is reducing the optimal utilization of water reservoirs. The work presented in this study aims to investing the use of Chemical films as Evapo retardars for reduction of evaporation from the open water surface so as to increase the storage efficiency. Particular emphasis will be on practical procedures and techniques that professionals can use to estimate and/or to suppress evaporation from shallow water bodies. The natural evaporation loss taking place from pan evaporimeters of two or more chemicals were observed and compared. The important meteorological factors affecting the natural evaporation such as Temperature, Relative Humidity, Wind Velocity, Sunshine Hours, etc. were also observed. Cetyl and Stearyl Alcohols were selected to reduce the evaporation during the study period in Newasa Phata Ahmednagar region with Class-A evaporation pan

Photoluminescence properties of europium doped di-strontium magnesium di-silicate phosphor by solid state reaction method

Europium doped di-strontium magnesium di-silicate phosphor namely (Sr2MgSi2O7:Eu3+) was prepared by the traditional high temperature solid state reaction method. The phase structure of sintered phosphor was akermanite type structure which belongs to the tetragonal crystallography with space group P42¯1m, this structure is a member of the melilite group and forms a layered compound. The EDX and FTIR spectra confirm the present elements in Sr2MgSi2O7:Eu3+ phosphor. Photoluminescence measurements showed that the phosphor exhibited strong emission peak with good intensity, corresponding to 5D0 → 7F2 (613 nm) red emission and weak 5D0 → 7F1 (590 nm) orange emission. The excitation spectra monitored at 613 nm show broad band from 220 to 300 nm ascribed to O–Eu charge-transfer band (CTB) centered at about 269 nm, and the other peaks in the range of 300–400 nm originated from f–f transitions of Eu3+ ions. The strongest band at 395 nm can be assigned to 7F0 / 5L6 transition of Eu3+ ions due to the typical f–f transitions within Eu3+ of 4f6 configuration

Evaporation Losses Control in Water Surface by Chemicals

The extremely high rate of Evaporation from water surfaces day by day is reducing the optimal utilization of water reservoirs. The work presented in this study aims to investing the use of Chemical films as Evapo retardars for reduction of evaporation from the open water surface so as to increase the storage efficiency. Particular emphasis will be on practical procedures and techniques that professionals can use to estimate and/or to suppress evaporation from shallow water bodies. The natural evaporation loss taking place from pan evaporimeters of two or more chemicals were observed and compared. The important meteorological factors affecting the natural evaporation such as Temperature, Relative Humidity, Wind Velocity, Sunshine Hours, etc. were also observed. Cetyl and Stearyl Alcohols were selected to reduce the evaporation during the study period in Newasa Phata Ahmednagar region with Class-A evaporation pan

Food Restriction-Induced Changes in Gonadotropin-Inhibiting Hormone Cells are Associated with Changes in Sexual Motivation and Food Hoarding, but not Sexual Performance and Food Intake.

We hypothesized that putative anorectic and orexigenic peptides control the motivation to engage in either ingestive or sex behaviors, and these peptides function to optimize reproductive success in environments where energy fluctuates. Here, the putative orexigenic peptide, gonadotropin-inhibiting hormone (GnIH, also known as RFamide-related peptide-3), and the putative anorectic hormones leptin, insulin, and estradiol were examined during the course of food restriction. Groups of female Syrian hamsters were restricted to 75% of their ad libitum food intake or fed ad libitum for 4, 8, or 12 days. Two other groups were food-restricted for 12 days and then re-fed ad libitum for 4 or 8 days. After testing for sex and ingestive behavior, blood was sampled and assayed for peripheral hormones. Brains were immunohistochemically double-labeled for GnIH and the protein product of the immediate early gene, c-fos, a marker of cellular activation. Food hoarding, the number of double-labeled cells, and the percent of GnIH-Ir cells labeled with Fos-Ir were significantly increased at 8 and 12 days after the start of food restriction. Vaginal scent marking and GnIH-Ir cell number significantly decreased after the same duration of restriction. Food hoarding, but not food intake, was significantly positively correlated with cellular activation in GnIH-Ir cells. Vaginal scent marking was significantly negatively correlated with cellular activation in GnIH-Ir cells. There were no significant effects of food restriction on plasma insulin, leptin, estradiol, or progesterone concentrations. In the dorsomedial hypothalamus (DMH) of energetically challenged females, strong projections from NPY-Ir cells were found in close apposition to GnIH-Ir cells. Together these results are consistent with the idea that metabolic signals influence sexual and ingestive motivation via NPY fibers that project to GnIH cells in the DMH